Stem cell-like properties of dormant cells in ovarian epithelial carcinoma transplantation tumors

Objective: To examine the stem cell-like properties of dormant cells in ovarian epithelial carcinoma transplantation tumors. Methods: The PKH26-labeled human ovarian cancer SKOV3 cells were inoculated subcutaneously in nude mice. According to the fluorescence intensity of PKH2, the tumor cells were divided into 3 groups using FCM method: PKH26 cells with high fluorescence retention (PKH26hi cells), PKH26 cells with low fluorescence retention (PKH26low cells), and PKH26 cells with fluorescence quenched completely (PKH26neg cells). The cell cycle of PKH26hi, PKH26low and PKH26neg SKOV3 cells was detected by FCM method. The mRNAs and proteins of stem cell markers octamer-binding protein 3/4 (OCT3/4), CD133, CD177 and Nanog were examined by real-time fluorescence-based quantitative PCR and Western blotting. The colony forming ability of PKH26hi, PKH26low and PKH26neg SKOV3 cells in vitro was observed by plate colony formation assay, and the tumorigenic ability in vivo was observed in nude mice. Results: The percentage of G0/G1 cells in PKH26hi SKOV3 cells was higher than those in PKH26low and PKH26neg cells (both P < 0.05). The mRNA and protein expression levels of stem cell markers OCT3/4, CD133, CD117 and Nanog in PKH26hi were higher than those in PKH26low and PKH26neg SKOV3 cells (all P < 0.05). The abilities of in vitro colony formation of PKH26hi SKOV3 cells and their tumorigenesis in nude mice were significantly higher than those of PKH26low cells and PKH26neg SKOV3 cells (both P < 0.05). Conclusion: PKH26hi cells in ovarian cancer SKOV3 cell xenografts in nude mice have stem cell-like properties. DOI:10.3781/j.issn.1000-7431.2018.11.562